‘The result is widespread, rapid declines of pollinators across continents …’
FRISCO — Canadian researchers say North American and European bumblebees are being squeezed in a “climate vise” that’s compressing their habitat.
In their study, the scientists found that it’s getting too warm at the southern end of their range, but the bees haven’t been able to expand northward into cooler territory.
“The result is widespread, rapid declines of pollinators across continents, effects that are not due to pesticide use or habitat loss. It looks like it’s just too hot,” said Professor Jeremy Kerr, Macroecology and Conservation chair at the University of Ottawa.
The scientists said their findings, published in Science, leave little doubt that climate change is having a significant impact on bumblebee species in North America and Europe.
When the climate warms, many wildlife species move poleward in search of cooler temperatures. But that hasn’t happened so far with bumblebees.
“Climate change may be making things too hot for them in the south, but is not pulling them north as expected,” said Paul Galpern, Assistant Professor of Landscape Ecology in the Faculty of Environmental Design, University of Calgary, co-author of study.
“Bumblebee species play critical roles as wild pollinators, not just for crops but of all sorts of plants,” Galpern said. “They provide an important service to ecosystems. They help plants produce fruits, seeds and this in turn provides both food and habitat for other animals, and so on.”
The researchers used more than half a million observations compiled from museum collections and citizen scientist collectors in North America and Europe spanning 100 years. The detailed records enabled the scientists to track thirty one bumblebee species in North America and thirty-six in Europe.
“We don’t know for sure what is causing a stagnation at the northern end of things. Bees should be able to start new colonies in places they did not historically occupy. But we don’t know why this is happening so slowly that it looks like the ranges are not moving at all,” said Galpern. “This all points to the fact that bumble bees are at risk, and the services that they provide are increasingly threatened by human-caused climate change.”